Ear tags generally comprise a wall with a female head and a wall with a male punch, said walls carrying identifying information. As they are affixed, by means of pliers, the male punch pierces the animal's ear and is housed in the female head where it is secured so that it cannot be separated from the female head. Necessary rigidity is provided by the pin of the pliers, which is housed in the hollow shaft of the punch. This punch is generally closed.
Generally, the female heads providing the best guarantee of inviolability for the completed assembly, and thus the inviolability of the marking achieved, are closed heads.
Closed heads have only one orifice, that through which the punch passes. This is secured in position, by known means, with a radial collar behind its pointed end, distal in relation to the tag of which it forms a non-distinct part.
The collar of the punch is locked into the female head, which is provided with ribs, teeth or other means that do not prevent the penetration of the punch but do prevent its withdrawal.
In a particular embodiment of the ear tag, the closed female head is made of a synthetic material, duplicate moulded on the wall and having a Shore hardness such that is difficult to pierce or cut it to perform any procedure on the end of the punch intended to remove it from the head.
At present, the ear tags that are most often used are tags with a closed head.
Tags with an open head are also available on the market, said tags each display an orifice through which the nose of the punch, with its collar, penetrates into an open tubular receptacle, that is to say having an orifice at its free end.
The use of ear tags for marking animals is a widespread practice in all livestock-breeding countries to ensure the tracking of bred animals destined for human consumption.
These markings and the data relating to the animal are generally centralised in computerised data banks that can be accessed for updating or information retrieval by all concerned: breeders, fatteners, veterinary services etc . . . right down to the distribution networks.
The pursuit of maximum security in the identification of the animal leads to the sampling of organic matter, which may be stored with a view to DNA analysis.
Patent WO 99 61 882 attempts a solution to this effect, and proposes a device and a procedure intended to enable a sample of organic tissue to be taken. This patent describes a receptacle for the sample and a sampling tool in the form of a cutting die that locks into the receptacle with the sampled organic matter.
The receptacle and the punch may be combined with an ear tag and carry the same markings.
Although it is indicated in this patent that it is possible to accomplish the sampling at the same time as affixing the ear tag, no technical information is provided to this effect, and it is not evident that this is possible at one and the same time.
In any case, since the sampling tool must necessarily be borne by the punch on one jaw of the ear-tagging pliers and the receptacle by the other jaw of the pliers, this is only feasible for tags with open heads that are capable of being traversed by the punch holder on the pliers and the sampling tool.
It is known that this type of tag is not very secure and is therefore little used.
Patent DE 197 40 429 describes a procedure and device similar to the preceding one, which is also limited to the use of an open-headed tag.
Patent EP 1 060 662 describes an ear tag of the abovementioned type wherein the male punch has at its end a circular cutting means which is detachable from the punch and is housed in a capsule borne in a perforation emerging at the back of the female head.
The device according to this patent is not applicable to ear tags with a closed head.
Furthermore, the substantial diameter of the cutting element makes the penetration of the male punch into the ear wall difficult.